1. Field of Invention
Exemplary aspects of the present invention relate to an illumination device, an image display device, and a projector. Specifically, the exemplary aspects of present invention relate to an illumination device to illuminate with uniform illumination intensity a spatial light modulation device, such as a liquid-crystal light valve or tilt mirror device, to an image display device equipped with such an illumination device, and to a projector to display an image by causing the illumination light modulated with the image display device to fall on a projection lens and projecting the illumination light from the projection lens onto a screen or the like.
2. Description of Related Art
The following related art methods vary the brightness of the illumination light in illumination devices to supply an illumination light to an image display device or the like. A method to vary the brightness of the illumination light by limiting the luminous flux with a variable diaphragm. See JP-A-2002-72361). A method to vary the brightness with an optical modulator, such as a liquid-crystal panel. See JP-A-2001-100689. A method to vary the brightness of the illumination light by varying the brightness of the lamp of a light source. See JP-A-6-102484.